Teen stabs 11-year-old sister 40 times for being ungrateful - Yahoo7

A 14-year-old girl has been charged with first-degree murder over the death of her younger sister who was stabbed more than 30 times after a sibling fight turned violent.

Dora Betancourt, 11, was allegedly stabbed nearly 40 times by her older sister over the child's supposed ingratitude, according to the Chicago Tribune.

Police say Dora's older sister, who remains unnamed, called for an ambulance and claimed a Hispanic man had broken into their Chicago home before stabbing the 11-year-old in the neck, chest and arms.

Dora Betancourt, who was stabbed more than 30 times by her older sister. Photo: Supplied.

After a strand of the older sister's hair was found on Dora's lifeless body, police say the older sister confessed to the frenzied attack in which she shouted a reason for the attack each time she stabbed her younger sister with a kitchen knife.

"The young girl's body had so many wounds they couldn't count them all ... [and] were so deep they punctured her lung," the Lake County Medical Examiner's Office told CBS Chicago.

Coroner Dr. Thomas Rudd said there were indications that the younger girl fought for her life, including defensive wounds on her left hand that indicated she "probably grabbed the knife" and a defensive wound on her right thumb.

During a court hearing, prosecutors said the suspect told authorities the 11-year-old didn't appreciate all she had done for her, including making dinner and doing the younger girl's chores.

A fundraising drive has been organised to help pay for the cost of the 11-year-old's funeral. Photo: GoFundMe

No adult was home at the time of the slaying. The discovery of the body Tuesday morning prompted a brief lockdown at nearby schools.

"We are very confident this is an isolated incident and there are no other concerns to the neighbours and or the community around it," Mundelein police Chief Eric Guenther said.

The victim and the suspect attended St. John's Lutheran School in Libertyville.

"We are deeply saddened by the loss of one of our children," school spokesman Steven C. Fuoco told the Daily Herald in Arlington Heights. "We recognize this is a very difficult time for the family, friends and classmates. We have made arrangements for spiritual and professional assistance for our school family."